In the auto industry, there is a movement towards developing adaptive headlights. Generally, adaptive lighting systems use feedback from imaging systems or other sensors to control the brightness and distribution of the projected light from a light source. Some adaptive headlights are designed to dim or brighten individually controllable regions. In use, adaptive headlights attempt to account for conditions of a vehicle and avoid illuminating unwanted locations in front of the vehicle. For example, when a vehicle goes over a bump in the road, the projected light from the headlight of the vehicle may jolt vertically, causing bright flashes projected to an oncoming vehicle or pedestrians. Adaptive headlights attempt to account for this vertical jolting of the light by adjusting the position of a projected beam down when the bump is detected. Further, the unstable illumination due to normal vehicle movements from bumps, potholes, and the like can complicate signal extraction in real-time computer vision systems using structured light.
Many conventional adaptive headlights have limitations that lessen the effectiveness of the system. For example, high resolution illumination of a scene is typically limited, as most adaptive lighting systems are attenuation based. Further, these systems also are limited as to the intrinsic brightness that can be projected and can also be limited in the depth of field for a projected image, such as when the in-focus image is limited to a plane. More importantly, adaptive headlight systems typically are not able to respond to changing conditions of the vehicle fast enough to account for rapid movements of the vehicle.
Thus, there is a need for a spatial light modulator in a high speed imaged-based feedback system which can modify the light distribution and/or update a scene illumination pattern faster than the inertial changes experienced during an instability event, and with sufficient stroke to take out the orientation and position errors encountered, among other needs and advantages.